Switch machine for railway spring switches



Feb. 15, 1944. w. K. HQWE I 2,341,713

SWITCH MACHIYI-JE FOR RA LWAY SPRING sw ITcHEs Filed Nov. 20, 1940iNVENTOR I leaf L2,

ATTORNEY Patented Feb. 15, 1944 SWITCH MACHINE FOR RAILWAY SPRINGSWITCHES Winthrop K. Howe, Rochester, N. Y., assignor to General RailwaySignal Company, Rochester,

Application November 20, 1940, ,Serial No. 366,399

Claims.

This invention relates in general to switch machines for railwayswitches, and has more particular reference to machines for springswitches which are lockable in normal position and-can be hand operatedto either normal or reverse position, and are trailableby-cars to eitherposition.

The machine forming the subject matter of the present invention, whichcan be operateclby hand to either position, is, when operated fromnormal to reverse position, first unlocked, and then thrown, and whenoperated from reverse to normal, first thrown and then locked.

The throw-rod for the track switch includes a spring bufier, whichbiases the switch to the .position at which it is set, and permitstrailing of the switch by compression of the spring of the butter. Theback-slap tendency of the switch, under the influence of the compressedspring, .between the passages ofsuccessive car wheels,.is prevented by abuffer or dash-pot mechanism in the spring buffer.

When the switch is trailed from normal it is of course necessary tofirst unlock it before the switch pointscan be ,moved, and this isaccomplished by means .of a track treadle operated by the trailing carsomewhat prior to itsreaching the switch points.

The various parts areso arrangedthat theunlocking treadle, which is.biased to its normal position by resilient means, is prevtned fromslapping back .to its normal position between passages of successive carwheels,.by .the samedashpot mechanism that is employed .for preventingthe back slap of thespringswitch.

Since .a portion of the movement of a .usual hand switch stand handle isused for switch unlocking, a gain-stroke device is employed to mu1-tiply. movement on hand throwing the switch so that the usual arc ofmovement of the hand switchstand handle is suflicient to not only11nlock the switch but to move it to extreme position.

The machine of this invention can be employed for switches facing eitherright or left hand, by partlyrotating the machine, .and then reversingcertain of the operatingparts, as will appear below.

One form of .the invention .is shown in the accompanying .drawing, whichis wholly diagrammaticin form, issolely ,for the purpose ofillustration,;and.is not employed in .any way whatsoeverin 'a limitingsense. In the drawing- Fig. 1 is .a wholly schematic view of one .formof this invention.

Fig. 2 is 1a detailed1view toan enlarged scale,

of a spring buffer constituting part of this invention.

Referring now to the drawing, and first to Fig. 1, there is here shownastretch of main track constituted by track rails I, with a track switch'I'Sleacling from .the main track to a passing sidmg.

A track treadle Tr is positioned. adjacent one of the rails of the trackswitch so as to be operated by the wheels of a car passing from thesiding and onto the main track, just prior to the wheels reaching theswitch points. This treadle is shown in a wholly diagrammatic manner, asconstituted by a bar 2 pivoted to support legs 3, and depressable by acar wheel on the adjacent switch rail, so as to ,movean operating leverd downwardly as viewed in the drawing. The lever 4 on moving downwardlycompresses a spring 5 normally biasing the'treadle to its raised normalposition, to thereby operate a crank 6 pivoted at '6 and exert .a pullto theleft on an unlocking rod 1 which .pivotally carries ,a pinion 8.

The track switch is connected to a usual lock rod LR-which has a notch 9for receiving a lock plunger Ill. The lock plunger it is connected to arack ll, slidable in a support l2, and meshing with the pinion 8. A rack13, slidable in a support l4, also meshes with pinion 8, on the sideopposite to rack ll, and carries a pin 15 engaged in a slot [6 in oneendof a leverll, pivoted at its other end as at 1.8 to. a fixed pivot inthe machine.

Lever ll, intermediate its ends, carries an operating pin l9, receivedin'a cam slot in an operated member OM. Thisslot has an inclined portion20 which ;can be considered an unlocking portion, and a vertical portion2| whichis a lost motion portion.

The operating member OM carries a second cam slot having a lost motionswitch locking vertical portion 22, and a curved generally horizontalportion 23, which can be considered a switch operating portion.

In this second slot is a pin'2 l carried at one end by one end of anoperating plate 25, pivoted at its other end to a fixed pivot pin 26.This plate 25 carries two pins 21 and 28, which are receivedrespectively in an intermediate hole in a second operating plate 29which is pivoted. on thepin 26 and inan edge groove 30 therein, therebeing an opposed edge groove 3| in the plate, the

. function of which will appear below.

Plate 29 atitsend opposite its fixed pivot 26, carries -a;pin -32receivable in a horizontal slot 33 in the machine throw-rod TR. Thisthrow-rod, at its other end, is connected to a rod 34 entering thespring buffer SB while the casing connection portion 44 on the casing ofthe spring buffer is connected to the track switch points by a rod 35.

A detector rod DR for the track switch is shown as connecting the trackswitch with the switch machine which latter is indicated by therectangle SM. This detector rod, however, is not involved in the presentinvention.

The switch machine has a usual hand-throw rod HT which carries theoperating member OM referred to above, and is connected at its lower endto a usual hand switch stand HS. .Asviewed in Fig. 1, this connectionincludes a reciprocating operating rod 31, which is slotted to receive acam 38 on a rotatable member 39 which can be rotated substantially 180by the handthrow operating handle 46. The handle 46 can be moved fromits shown position to a position opposite thereto, and any usual latchor lock means can be employed for holding the handle in its thrownposition. This handle is also furnished with a usual weight 4| forbiasing it to its thrown position. Furthermore, the slope of the cam 38is such that a backward drive from the switch to the handle isprevented.

As stated above, the drawing is wholly schematic and no attempt has beenmade to show any actual construction, or actual sizes or proportions.Before describing the operation of the machine, as described above, itmight be best to consider the details of construction of the springbufier SB.

Referring to Fig. 2, the spring buffer is shown as having a casing 43with two ends 44 and 45 bolted thereto, the end 44 being connected byrod 35 to the track switch and the end 45 having an opening for slidablyreceiving the rod 34 to which the throw-rod of the machine is connected.Rod 34, slidable in the casing, is packed liquid tight by packing 46. Anopening 41 is provided for filling the casing with oil, or othersuitable liquid, and is normally closed by a plug 48.

Within the casing is a partition 49 dividing the casing into a reservoir50, and a piston chamber connected to the reservoir by an opening KilThe piston chamber contains, at one end, a piston 53, and at the otherend a piston 54 with a spring 55 trapped between the two pistons andcomprised so as to force them away from each other. The pistons are tiedtogether by heads 56 and 51 on the rod 34 whereby each piston can bemoved inwardly on the rod 34 toward the other piston and against thespring tension but cannot be moved outwardly away from each other.

The piston 53 is furnished with a check valve 58 urged by a spring 59 toclose ports 60 in the piston, the spring 59 being trapped between thevalve 58 and a head 6| fixed to the piston. Valve 58 has a bleed passage62 therein for a purpose to be described below.

The other piston 54 is equipped identically with the one just describedwith reference to its valve 63, spring 64, holding head 65, and bleedport 66.

The partition 49 at each end has an inner longitudinal groove 6'! and 68to form a relatively large bi-pass around the piston. This grooveextends only a-short distance inwardly from each closed, the onlycommunication past the piston is through its bleed port.

As shown in Fig. 1, rod 35, connecting the buffer with the track switchcarries a stop lug 69 against which a treadle holding rod 10, pivoted atH to a fixed point, and connected at T2 to a rod 73 normally bears, asshown.

The machine, as described above, permits operation of the spring switchby hand to either extreme position in which the spring buiferresiliently holding the switch against movement away from its thrownposition so permitting trailing thereof. In the event the switch betrailed from its normal to its reverse position, the spring buffer isbrought into operation and returns the switch points to their originalposition after the train has passed, and during the passage ofsuccessive wheels exerts a dashpot or retarding effect to prevent theswitch points from slapping against the rails. In this case, the firstwheel of the car first passes over the treadle to unlock the trackswitch, and the spring 5 which returns the treadle to normal position isprevented from slapping the treadle against the car wheels as successivewheels pass over it, by the same spring buffer that prevents slapping ofthe switch points between successive car wheel passages.

Consider now the operation of the machine in some detail. An east boundtrain passing from the siding and onto the main track depresses thetreadle just before it reaches the switch points to thereby compressspring 5 and move rod 1 to the left, as viewed in the drawing. Sincerack I3 is held stationary by the hand operated switch stand, pinion 8rolls on rack 13 and moves rack I l to the left at twice the speed ofrod 1 to draw lock bolt l0 out of engagement with lock rod LR to therebyunlock the switch.

Immediately thereafter, the car wheels force the switch points to theirreverse position. In doing this, rod 35, connected to the casing of thespring buffer SB, is moved in a direction toward the track to therebycompress the buffer spring while the pressure of fluid between thepistons opens check valve 58 and allows the fluid to freely pass beyondthe check valve and fill the space opened up between head 44 and theouter face of the piston. Thus the switch is quickly. moved against thepressure of spring 55 while the fluid can freely pass from one side ofthe piston to the other.

When the switch is released from the pressure of a pair of car wheels,the spring of the buifer tends to return it, and likewise, the spring 5tends to return the treadle. However, when the treadle was depressed,arm 16 moved towardthe track and away from stop lug 69, and when theswitch was trailed, the stoplug 69 was moved up against arm 10 in itstreadle depressed position. Accordingly, the spring bufier acts toprevent not only the switch points from slapping against the rails, butalso the treadle from moving back to its normal position andslappingagainst the wheels. This buffing actionv is producedhy the,liquid which has passed beyond the valve 58, and which on attempting toreturn to the central part of the spring chamber is largelypreventedfrom I doing so by the check valve since the piston has passed beyondthe side port 67 and has a tight fit in the chamber. The bleed portallows so little liquid flow that practically no return'movement of theswitch or treadle is permitted.

Upon the train clearing the switch the switch points return to normalposition by slowmov'ement at first, due to fluid passing through thebleed port 62, and after the piston has passed opposite the large port61 and the fluid can pass more freely by a relatively fast movement tothe normal position. At the same time, the treadle is allowed to returnto normal position, due to lug 69 moving out of the way of arm 10 andthe switch is locked up by means of pinion 8 operating rack II and withit look bolt l0.

With the track switch in its reverse position, it is unlocked, and atrain, on trailing it to normal position, moves the spring bufier casingaway from the track rails to open check valve 63, compress spring 55,.and produce a bllfi'ing action at this valve.(63) end, in the samemanner as described above.

"Thus, the spring bufier not only resiliently holds the track switchagainst movement away from its thrown position, but, uponbeing trailed,it prevents not only the switch, but also the treadle, respectively,from slapping against the rails and car wheels, as the wheels pass.

The treadle is shown in a purely conventional manner as a depressabletreadle inclined in the direction of the travel of the car; Thistreadle, however, can be of any other usual type so long as the passageof a car causes the movement of arm 1 and pinion 8. The treadle ispositioned with respect to the switch points so that it is in depressedposition due to a wheel operating it at the time forward car wheels arein positionto'move the switch points. I

Considering now the operation of thetrack switch by the hand switchstand, letgus assume that it is desired to move the switch by hand toits reverse position. Lever 48 of the switch stand is moved to itsreverse position, thereby causing cam 38 to move hand throw rod HT andwith it operating member OM forward toward the track.

During the first part of the movement of member OM pin 19 is moved tothe right due to the inclined portion 26 of the cam slot, therebyswinging lever i1 clockwise so as ,to move rack l3 to the right, andthrough the pinion 8 move rack H to the left so as to unlock the trackswitch. After the switch is unlocked, pin I9 is held against furthersidewise movement by means of the vertical portion H of the cam slot.

By the time unlocking has taken place, pin 24 has passed through thevertical slot portion 22 and is received in the horizontal slot portion23. Continued movement of the handthrow rod turns plate 25 clockwise onits pivot :pin 26 to thereby turn plate 29 clockwise through theconnecting pins 21 and 28. This turning of the plate 29 causes pin 32 tomove the switch-throw rod TR in a direction toward the track switch tothereby throw the track switch to its reverse position and at the sametime through lug 69 and rod 1'0 to depress the treadle. The treadlespring 5 is relatively weak and requires perhaps 50 pounds pressure tooperate it and hence no very large extra load is imposed on the handswitch stand operation.

n moving the switch from its reverse to its normalposition, the handswitch stand lever 46 is returned to its shown position, and theoperations, as above described, take place in reverse order, That is,the switch is first thrown, and then is locked up.

During the hand operation of the switch, the spring buiier moves as. aunit, and the buffer spring 55, which is a very strong spring is notcompressed.

is received in the other side groove 3!.

In the usual hand switch stand, a movement of the hand lever through 180completely throws the switch from one extreme position to the other.When the first portion of the lever movement is employed in unlockingthe switch, the remaining portion of the movement is insufficient tocause the complete movement of the switch points unless there be amultiplying effeet, or gain-stroke mechanism, as constituted by thepivoted operating plates 25 and 29.

In case it is desired to use the machine in connection with a left handtrack switch as one at the other end of the passing siding, it is soconstituted that this can readily be done. All that is necessary is torotate the machine 180 to bring the lower end of the machine in positionto face the track switch. Then the hand-throw rod must be turned endforend in the machine and "turned over so that the bottom of operatingmember OM is on top. Furthermore, the operating plate 25 must be shiftedwith respect to the operating plate 29 so that pin 28 is received in thehole in the center of plate 29, and pin 2'! With these simple changes,the machine can be readily connected to the track switch and the handswitch stand, the. treadle and the bufier, and will operate in themanner described above.

The above rather specific description of one form of this invention hasbeen givensolely by way of example, and is not intended in any mannerwhatsoever in a limiting sense. It is to be understood that variousmodifications, adaptations and alterations can be applied to meet therequirements of practice, without in any manner departing from thespirit or scope of the invention except as limited by the appendedclaims.

What I claim is:

1. In spring track switch operating means, in combination, a trackswitch movable to normal and reverse positions, elastic means resistingmovement due to a trailing car move of the switch from either ofsaid-positions, means look-- ing the switch in at least one of saidpositions, a car-operated track device connected to the locking means,means to bias the track device to inoperative position, the device beingpositioned to be moved by a switch trailing car to its operative switchunlocking position, a retarding means, and means operatively connectingboth the switch and the track device to the retarding means so as toretard movement of the switch from intermediate positions and movementof the track device from its operative position.

' 2. In track switch operating means, in combination, a track switchmovable to normal and reverse positions, locking means to lock theswitch in one of said positions, switch operating means for operatingand locking, and for unlocking and operating, the switch, a springbuffer operatively interconnecting the operating means and the switch,resilient means in the buffer resisting movement of the switch fromeither normal or reverse position due to force acting directly on theswitch, automatic car actuated lock operating trackway means adjacentthe switch and normally positioned to be moved to reverse, unlockinposition by a car approaching the switch to trail the switch from thetrack rail against which the switch is set in its locked position,resilient means biasing the automatic lock operating means to saidnormal locking position, bufiing means in the bufier for retarding thespeed of return of the switch to either normal or reverse positionsafter being trailed through,

and means connecting the automatic operating means to the buifing meansso that the buiTer retards the speed of return of the lock operatingmeans to normal position from its reverse position.

3. In track switch operating means, in combination, a track switchmovable to normal and reverse positions, locking means to lock theswitch in one of said positions, switch operating means for operatingand locking, and for unlocking and operating, the switch, a springbuffer operatively inter-connecting the operating means and the switch,resilient means in the bufier resisting movement of the switch fromeither normal or reverse position due to force acting directly on theswitch, automatic car actuated lock operating trackway means adjacentthe switch and normally positioned to be moved to reverse, unlockingposition by a car approaching the switch to trail the switch from thetrack rail against which the switch is set in its locked position,resilient means biasing the automatic lock operating means to saidnonnal locking position, buffing means in the buffer for retarding thespeed of return of the switch to either normal or reverse positionsafter being trailed through, and means connecting the automatic lockoperating means to the buffing means so that the buffer retards thespeed of return of the lock operating means to normal positio from itsreverse position.

4. In track switch operating means, in combination, a track switchmovable to normal and reverse positions, locking means to lock theswitch in one of said positions, a switch throw rod, switch operatingmeans including the throw rod, for locking, unlocking, and operating theswitch, said switch operating means including means to hold the throwrod against movement during the unlocking period, a spring bufieroperatively inter-connecting the throw rod and the switch, resilientmeans in the buffer resisting movement of the switch from either normalor reverse position due to force acting directly on the switch,automatic car actuated lock operatq ing trackway means adjacenttheswitch and normally positioned to bev moved to reverse,=unlockingposition by a car so approaching the switch as to trail the switch fromthe track rail against which the switch isset in its locked position,re-r silient means biasing the automatic lock operating means to saidnormal locking position, bufiing means in the bufier for retarding thespeed of return of the switch to either normal or reverse positionsafter being trailed through, and means connecting the automatic lockoperating means to the butting means so that the bufier retards thespeed of return of the lock operating means to normal position from itsreverse position.-

5. In track switch operating means, in combination, a track switchmovable to normal and reverse positions, locking means'including alockrod and a lock bolt for locking the switchinnormal position, a switchthrow rod, switch operating means including the throw rod, for locking,unlocking, and operating the switch, a spring bufier operativelyinter-connecting the throw rod and the switch, resilient means in thebufier resisting movement of the switch from either normal or reverseposition due to force acting on the switch other than through the switchoperating means, automatic car actuated lock operating trackway meansadjacent the switch and-positioned to be moved to reverse, unlockingposition by car approaching the switch so as to trail the switch fromthe track rail against which it is set in its locked position, resilientmeans biasing the lock operating means to the normal locking position,buifing means in the buffer for retarding the speed of return of theswitch to either normal or reverse after being trailed through, meansconnecting the automatic lock operatin means to the bufiing means so asto retard the speed of return of the lock operating means to normalposition from its reverse position, saidswitch operating means includingmeans to hold the throw rod against movement during the unlockingperiod, and means to hold the lock bolt stationary during the switchthrowing period.

WINTHROP K. HOWE.

